Wire grip for electrical fittings



F. w. cLAR Ki 2,446,262 WIRE GRIP FOR ELECTRICAL FITTINGS Aug13, 1948.

Filed May 30', 1945 mmvrox FLOYD W. CLARK Ag em Patented Aug. 3, 1948 WIRE GRIP FOR ELECTRICAL FITTINGS Floyd w. Clark. San Fernando, Calif., assignor to Lockheed Aircraft Corporation, Burbank, Calif.

Application May 30,1945, Serial No. 596,757 6 Claims. (cl. 113-322) This invention relates to electrical connectors and fittings, and relates more particularly to securing, supporting or clamping devices for the electrical conductors associated with such electrical equipment.

Where detachable or releasable electrical connectors. such as plugs and sockets are employed, it is important to provide means for securing the conductors to the plug or other fittings, so as to relieve the binding posts, soldering, and other wire attaching means of the strain attending the connection and disconnection of the fitting. Furthermore, in aircraft installations where releasable'plugs are used, it is necessary to relieve the electrical contact pins, soldering, or the like, of the weight of the free wires. It has been the practice in such situations to provide screw actuated split clamps, or similar devices, for clamping about the wires where they extend from the plug or fitting. Such wire clamps usually complicate the assembling of the wires and do not assure a permanent grip or retention of the conductor.

It is a general object of the present invention to provide a'simple, practical and inexpensive device for securing the wires to the bodies of plugs, sockets and similar electrical fittings in order to relieve the binding screws and soldering of the weight of the wires and the strains incident to connecting and disconnecting the fittings. The device of the present invention, directly transmits such loads and strains directly to the body of the fitting.

Another object of the invention is to provide a clamp or device of the character to, which embodies only three parts; namely, two identical clamp laws and a threaded coupling nut or sleeve. The two jaws may be inexpensively constructed of molded plastic, or the like, and being identical, may be fabricated by mass production methods. The sleeve or nut is a simple one-piece part and in the case of aircraft connectors, the usual closure throughout which reference will be made to the accompanying drawings wherein:

Figure l is a side elevation of a multi-wire plug of the kind employed in aircraft with the sleeve of the clamp appearing in transverse cross section and showing the jaws unactuated;

Figure 2 is a front end viewof the two jaws of the clamp:

Figure 3 is a side elevation of the two jaws prior to assembly;

Figure 41s an elevation of the inner face of one of the jaws; I

Figure 5 is a longitudinal sectional view of one of the jaws;

Figure 6 is an elevation of the inner end of another form of jaw of the invention; and

Figure 7 is a, longitudinal sectional view of a two-wire plug equipped with the'device of the invention.

I Thedevice of this invention may be incorpo- 'rated inor applied to electrical connectors, fitto handle a plurality of individual insulated wires W, and is adapted to be coupled with a complementary connector section (not shown) by an coupling nut serves as the clamp-jaw actuating this operation may be performed without tools of I any kind.

Other objects and features of the invention will become apparent from the following detailed disinternally threaded coupling sleeve Ill, rotatably arranged on the forward end of the shell or body I I of the plug. The rear portion of the plug body ll carries an external screw thread II. The rear end face of the tubular shell or body II is flat and normal to the longitudinal axis of the assembly. The present invention is not primarily concerned with the internal details of the plug P, and these features are omitted from the present disclosure.

The clamp or wire grip of the invention includes a coupling nut or sleeve l3 threaded on the body Ii of the plug P and two jaws I4 actuated by the sleeve it to grip and retain the wires W extending from the plug.

The coupling nut or sleeve i3 is a tubular member of metal, plastic or other suitable material provided with an internal thread for cooperating with the thread II of the plug body. The external surface of the sleeve I 3 may be knurled, corrugated, or provided with flat faces so that it may be readily screwed onto the fitting body II by hand or with the assistance of a tool. The outer end of the sleeve has an internal annular flange II. The flange ii presents an axially facing surface spaced from and opposing the aforementioned end face of the plug body ll. observed that the sleeve just described is an inexpensive one-piece, member.

The jaws H may be formed of a suitable plastic. such as a phenolic resin, although if desired, they may be constructed of metal or any other selected rigid material. It is a feature of the invention that the jaws I 4 may be identical to reduce the Itwillbe cost of manufacture. The assembly of the two v bodiment of the invention illustrated in Figures 1 to 5, the jaws have transversely extending teeth 9. There may be a plurality of spaced teeth 9 along each edge or face of each jaw. The teeth may, resemble spur gear teeth and are formed and related to closely mesh when the jaws are actuated or swung together, as will be later described.

Figure 6 illustrates a form of jaw provided at its inner side with axially extending teeth or ribs ii. In the particular case illustrated there are two such teeth extending along one face of the jaw, defining a groove ii for receiving a single axial tooth or rib It on the other jaw, it being understood that the two jaws of this form of the invention may be identical. Except for the configuration of the interfltting teeth or ,ribs It and ll, the jaws of Figure 6 may be of the same shape and construction as the jaws illustrated in Figures 1 to 5.

- Referring again to the structure of Figures 1 to 5, the jaws M are constructed todeflne a chana compact bundle. The forward portions of the convergent socket walls press inwardly against the wires W to grip the same, although the principal gripping engagement occurs in the forward parts of the jaws it. These forward parts of the jaws have flat Opposing inner surfaces 2| in spaced relation. defining a narrow rectangular gap or opening 0 best illustrated in Figure 2. The surfaces 2| are in forwardly converging relation so that the opening 0 is of forwardly diminishing capacity. The wires W extending through the opening 0 are tightly and effectively gripped by the surfaces 2! when the jaws are actuated as described below.

The base or rear portions of the jaws H are received within the sleeve l3. and have external flanges or lips 22 engaged by the flange ii of the sleeve. The lips 22 may be simple integralridges or projections on the jaws and their inner faces are preferably flush with the rear or base surfaces of the jaws. As illustrated in Figures 1 and .3, the base surfaces of the jaws I are pitched to converge forwardly. By reason of this inclination of the jaw faces, the lips 22 engage or bear on the end surface of the plug body II at diametrically opposite points. These form the fulcrum points of the jaws i4, whereby the jaws are supported for independent pivotal movement about spaced parallel axes. The flange ii of the sleeve ll cooperates with the lips 22, and when the sleeve is screwed inwardly along the plug body. this cooperation causes the two jaws to simultaneously pivot about the aforementioned fulcrum points. By reference to Figure 1 it will be seen that this causes the forward or outer portions of the jaws to swing or move together so that the wires W are gripped by the surfaces II and 2|. Thus. by merely screwing the sleeve. il inwardly on the plug. the jaws M are actuated to securely grip the wires.

In employing the device of the invention, the wires W are secured in the plug P in the usual manner to extend rearwardly-from the plug as illustrated. The sleeve I3 is unscrewed from the plug, and the jaws I 4 are assembled around the wires W to have their lips 22 within the sleeve. The nut or sleeve is then screwed onto the plug body I I and screwed tight to actuate the jaws. As above described, this pivots the jaws M together to tightly clamp and secure the bundle of wires. It is to be observed that the device may be installed and actuated without disturbing the wires W.

In Figure 7 I have illustrated the device of the invention incorporated'in a more or less conventional electrical plug. The plug illustrated includes a body 29 carrying the usual spaced contact tongues or prongs 30 and binding screws 3|. A two-wire insulated conductor 32 enters an opening 33 in the plug body and exposed end parts of its wires are secured by the screws ii. In this form of the invention, the sleeve or nut i3 is threaded directly onto the plug body 29, and the lips 22 of the jaws it are confined between the rear face of the plug body, and the flange it of the sleeve. The jaws it when actuated by inward screwing ofthe sleeve l3 grip the wire 32. It is to beunderstood that the inner active faces of the jaws ll may be shaped to properly grip vided an extremely simple inexpensive wire grip' or clamp that may be quickly assembled and operated. The device may be associated with electrical plugs and fittings of various kinds without altering or modifying the fittings.

Having described only typical forms of the invention, Ido not wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

I claim:

1. A device for usev with an electrical fitting having a wire extending therefrom and presenting an end face, the device comprising a pair of jaws assembled around the wire, the jaws each including an. end lip opposing and inclined with respect to said face so as to have pivotal engagement therewith, and each jaw having a recess for partially receiving the wireand teeth at opposite sides of the recess. a member-threaded on the fitting. and a flange on the member for coopscrewed onto the fitting, to pivot the jaws toward one another so that the walls of said recesses grip the wire and so that said teeth of the jaws are brought into close meshing engagement.

2. A device for use with an electrical fitting having a wire extending therefrom and presenting an end face, the device comprising a pair of jaws assembled around the wire, the jaws each including an end lip opposing and inclined with respect to said face was to have pivotal engagement therewith, inwardly projecting teeth on the jaws, the teeth of the two jaws being in interfitting relation, a member threaded on the fitting, and a flange on the member for cooperating with said lips, when the member is screwed onto the fitting, to pivot the jaws toward one another to grip the wire and to bring said jaws into close interfitting engagement.

3. A device for use with a fitting presenting an end face and having a wire extending therefrom, the device comprising apair of like jaws having opposing surfaces on their inner sides for gripping the wire, fianges on the inner ends of the jaws opposing said face of the fitting and diverging therefrom to each have a limited area of fulcrum engagement withthe face, an annular member threaded on the fitting, and an internal fiange .on the member extending around the jaws and having an end face for cooperating with said flanges of the jaws to urge them toward said face and thus pivot the jaws toward one another to grip the wire when themember is screwed inwardly along the fitting.

4. A device for use with a fitting presenting an end face and having a wire extending therefrom,

the device comprising a pair of like jaws having opposingsurfaces on their inner sides for gripping the wire, transversely extending teeth on the opposing inner sides of the jaws at opposite sides of said gripping surfaces, the teeth of the two jaws being in interfitting cooperation, flanges on the inner ends of the jaws opposing said face of the fitting and diverging therefrom to each have a limited area of fulcrum engagement with the face, an annular member threaded on the fit- 6 end face and having a wire extending therefrom, the device comprising a pair of like jaws having opposing surfaces on their inner sides for gripping the wire, axially extending teeth on the opposing in-ner sides of the jaws at opposite sides of said gripping surfaces, the teeth of the two jaws being in interfitting cooperation, flanges on the inner ends of the jaws opposing said face of the fitting and. diverging therefrom to each have a limited area of fulcrum engagement with the f ace, an annular member threaded on the fitting, and an internal flange on the member extending around the jaws and having an end face for cooperating with said flanges ofthe jaws to urge them toward said face and thus pivot the jaws toward one another to grip the wire when the member is screwed inwardly along the fitting.

6. A device for use with an electrical fitting having a wire extending therefrom and present ing an end face, the device comprising a pair of jaws assembled around'the wire, each jaw having an inner end surface pitched with respect to said face and opposing the same to have a point of fulcrum engagement therewith, an external shoulder on each jaw adjacent its inner end, said shoulders being pitched so as to converge toward the outer ends of the jaws, and a sleeve screwed on the fitting in surrounding relation to the inner portions of the jaws and engaging said pitched shoulders to simultaneously pivot the jaws to ward one another about said points to grip the wirewhen the sleeve is screwed inwardly on the fitting, the outer portions of the jaws being exposed and visible for inspection.

FLOYD W. CLARK.

40 file of this patent: I

ting, and an internal flange on the member ex- UN ITED STATES PATENT Number Name Date 885,836 Bullock, Jr. Apr. 28, 1908 1,181,451 Hubbell May 2, 1916 1,276,216 Hawthorne Aug. 20, 1918 1,703,046 Paiste Feb. 19, 1929 2,277,637 Eby' Mar. 24, 1942 FOREIGN PATENTS Number Country Date 593,266 Germany Feb. 23, 1934 

